In case anybody hasn't noticed, whenever a game goes up for free on various flash sales, they are sold out extremely fast. In most cases this is a matter of people botting the site to get them immediately as they go up for grabs. My suggestion would for the most part stop these bots in their tracks & allow legit customers to still get the games at a minimal price simply to verify they're not a bot.

My suggestion is rather than putting the game up for free, put it up for 1¢ rather then a quick checkout without any kind of card verification. Technically speaking this wouldn't even have to be a permanent charge, it could be a authorization charge just to make sure that the user has a valid card on file, which ends up getting refunded anyways. So basically it would still be free, but they wouldn't be able to complete the transaction unless a minimal authorization charge succeeded on their card. In most cases what happens when these games are acquired through botting, they are simply resold, so these botters are making a profit off of the free game offers from GOG, so I would like to see this type of manipulation put to a screeching halt.

There is one other form of botting that rather bothers me, but I'm not entirely sure on how we would deal with that. This has to do with upvote/downvote polls to keep a sale running for a shorter/longer period of time; I have seen sales go on for literally the remainder of the sale because the poll is botted to keep going up. I guess essentially you could use the same system I suggested above with a bunch of authorization charges that get reimbursed, but I think that might be taking the system a little too far, so there may be a better method (captcha can be easily worked around, so I can't really say I'd suggest that method).

Some digital retailers like to use cellphone/phone authorization to make sure a person is legit, I can't exactly say I like this method. First off I don't have a cellphone, so this method would end up resulting in loss of customers as they won't have the option to verify via text (personally I see this as a HUGE annoyance when my Yahoo account is attempting to get me to bind a cellphone number to it every time I log in where I can't verify it even if I add my landline number just to stop the "reminders"). Also I've had issues with other retailers such as GameFly & GamersGate where they claimed my phone number was a virtual device & not valid for authorization, which ended up postponing my ability to finish the purchase (some of those purchases actually got canceled when I couldn't complete them); my number is not a virtual device, it's a landline through CenturyLink, but some companies have it incorrectly categorized (bascially I'm trying to avoid purchasing from GameFly because I keep running into this; GamersGate is a little easier to work with on it & purchases can be canceled if they haven't gone through yet).

Technically, there are still transaction fees (paypal, currency change, Cyprus ...) so it's farther from free that you'd think.
The botting you speak of is to be expected but not proved AFAIK, I personally succeeded in getting one free game on one occasion, with my own fingers.
And finally , business wise, gog don't want to be known as the place when there is a sale, sometimes games are sold even cheaper. gog is the place when where there is a sale, games are given for free. The point is not to have faithful customers being rewarded in this case.

I have gotten a few free games before, but can't say I've ever gotten them from the insomniac sales because they're gone in under a minute most cases; there was never an authorization charge when I took advantage of the free sales. GOG started doing this thing where you would have to submit your email for a game later on, I assume this was to stop people from gaining multiple copies on the same IP. Regardless, it still happens; I'm merely making a suggestion to put a stop to it & an authorization charge is the best thing I can think of to stop bots in their tracks. I'm sure those bots could be recoded to simply allow the authorization fee if they know they're going to get it back however, so I can't entirely say this method is fullproof either...

I think GOG found a pretty good solution in the last Insomnia sale. There weren't free flash sales any longer, but instead everyone had the same (small) chance to get a game for free when he put a game in the cart and went to the checkout.

I suppose that works to a point; I guess I hadn't noticed they did that as I rarely ever SEE free games in the insomniac sales. Although making it a lottery isn't exactly the best way to deal with the problem because this still allows botters to manipulate the system, but this at least gives legit customers a chance to get the game as well.

It worked just fine. Click on a game, get a chance to win it. The only way botters could gank the system was to make a million accounts and try them all. At that point, they don't have key, they have it registered to one of a million accounts. If they want it that bad, they could just pirate it.

I like what they did last time and have no problems if I see it again.

There's also the option to use Captcha or answering a question, a small simple riddle. Like which numbers in this sequence aren't prime? What animal is this picture? (something simple like a duck). Maybe a short flash game of pin the tail on the donkey which requires interaction?

Of course as certain questions become well known or are cycled through, they would need to be changed out. Perhaps simple math problems, which characters aren't part of the simpsons, naming the last game you purchased... today's date. Trick questions, or perhaps confirmation in a PM that requires you to click a link to receive your game, expires in 10 minutes... Except for time zones... I go to bed usually an hour or so before any specials and deals start, so when i get up i missed the first 7 hours of the deals and there's a decent chance i lost 1-2 chances at free games since i didn't know about them...

Captcha is the answer me thinks.

Maybe. Lately when i use something with Captcha i end up refreshing it like 30 times before i can decipher it enough to type it in... Quite annoying...

Are we talking about GOG games here? If yes, that is already covered from Valentine's Day with Dungeon Keeper.
Click to get free game. If you don't have the game, the game is added to your account. If you have the game, get a gift code. Each customer can only use the offer once, and new customers will get the game, not a code to resell.

Captcha don't really work if it has a text entry field, they can easily be worked around. There are some that cannot be botted however, those have to do with a form of manipulation of the mouse. A couple of the ones that do work have to do with clicking on an image of what you're told to click on, I've even seem some that are like jigsaw puzzles. Anything with a text entry field can easily be automated using a simple GET command to get the answer.